While date formats are common issues address by designers and developers every day. However, date formats are a universal topic that plague people everywhere.

Here, I will explore common date formats, when they are used, and why there isn’t necessarily a best one to choose from.

Month-Day-Year vs Day-Month-Year

The majority of the world formats written dates in a manner that is actually logical: day-month-year. This pattern would be considered logical because day is less than month and month is less than year.

People in the United States, however, decided to do things differently and go with month-day-year. This pattern is not as logical, but reflects more accurately how people speak the date, as in “December 25, 2011.”

In an attempt to standardize date formats, ISO 8601 was released by the International Organization for Standardization way back in 1988.

ISO 8601 was designed for data elements, making it important for website designers and application developers. It never caught on outside of technology fields, but that is precisely where it causes the most heartache. The ISO standard dictates the format of year-month-day, going from the largest amount of time to the smallest.

Database date formats follows the ISO 8601 standard, but most interfaces do not. The average person is not comfortable reading dates in the ISO 8601 format even after 23 years, so conversions end up having to be made all in nearly all situations.

Dashes/Hyphens vs Slashes

Slashes and dashes are completely interchangeable. The ISO standard, of course, uses hyphens. Slashes may seem more commonplace, but using hyphens in your web design and development will make your life easier.

The Best Choice

It’s a rare occasion when I can’t solidly state the best way to approach something, but date formats have too many factors that dictate their usage. When dealing with technology especially, you will often find yourself at the mercy of existing code, and must simply cope with how that package/widget/service provides you with dates.

There is no single best method for all situations. Here are the best practices, though:

If your audience is solely in the United States, display MM-DD-YYYY. 12-25-2011

If your audience is outside the US, use DD-MM-YYYY. 25-12-2011

If your audience is both, code it on the fly or write the month name to avoid confusion. December 25, 2011